All patents, patent applications, and publications cited within this application are incorporated herein by reference to the same extent as if each individual patent, patent application or publication was specifically and individually incorporated by reference.
Surface Plasmon Resonance (SPR) spectroscopy is a powerful method capable of detecting molecular binding events at the nanometer scale by detecting changes in the effective refractive index or thickness of an adsorbed layer on or near an SPR active surface. When light is reflected from an SPR active medium at an angle greater than the critical angle, incident photons can generate surface plasmons. This phenomenon can be observed as a function of the reflected light intensity. The spatial difference of contrast can be acquired in an image format by employing a CCD camera as a detection system, namely SPR microscopy (SPRM).
Typically, SPR microscopy utilizes an angle of incidence of the irradiating beam at the prime SPR angle so that the system is conditioned to operate at its maximum linear response region. The procedure then involves rotating both sample and/or the detector and light source to establish the optimum optical pass configuration. Fine resolution rotation tables or linear diode arrays have been employed to provide the angular scanning function to obtain the SPR reflecting signal dip. Fixed wavelength, coherent angle scanning SPR employing dual rotation tables generally involves instruments having the optical pass configured in the horizontal plane. The physical size required for rotation stages offering fine resolution and providing enough torque to support the swing arms that hold either light source and/or detector gives the SPR instrument a large footprint. Thus, there is a need for an SPR instrument having a reduced footprint that allows SPR angle scanning.